PV+Battery Merchant

Hello !

I am trying to model the operation of a DC connected PV+Battery system, where the battery is charged from the clipped energy and does energy arbitrage (buy low, sell high)
I understand that arbitrage does not work best with SAM, and that there is a way to model it using a PPA price of 1usd/kWh and use ToD reflecting spot prices (which I have done)

My issue is the following : when comparing the case where the battery is only charged with clipped energy and the case where the battery can also charge from the grid, the results are a bit hard to understand. Specifically, the battery cahrges higher from the system in the case where grid charging is allowed versus the case when that is not allowed. Anyone know the reason for that ?

Attached the SAM file. The first simulation (Tierp_Clipping_with arbitrage) is the one where both charging from system and grid is allowed, while the other one charging is only from clipped energy. Take a look for example at Jun12/13 to see the difference i mention.

Best regards

Hi Youssef,

When the battery can charge from grid, on June 12, the battery charges from the grid and system between 15:00 and 18:00 when the TOD multipliers are lower so that the battery can discharge between 18:00 and 21:00 when they are higher.

When the battery cannot charge from the grid, the system power goes to the grid instead of charging the battery because charging the battery from the system and then discharging would result in battery losses.

Best regards,
Paul.

Hi Paul !

Thanks a lot for your answer.

 From my perspective, the clipping losses should have the same profile (independent if the battery can charge from the grid or not), and therefore i expected that "electricity to battery from system" would be the same in both cases. I guess SAM optimize the total power output of both the PV and battery to make the best economic result, instead of having the PV production/clipping static, and only optimizing battery dispatch.

Would you say my reasoning is correct ?

Thanks again for you help !